The present invention relates to seating, and in particular to a shell construction with selective back stiffening therefor.
Seating, such as tilt back chairs, swivel chairs, and the like, are typically provided with relatively rigid back constructions, which do not bend or flex in a horizontal plane. In modern office environments, the users of such chairs perform a wide variety of different tasks and activities from a seated position. Some of these tasks and activities require lateral motion and/or twisting of the upper back portion shoulder area of the seated user with respect to the user's torso. For example, when a user seated forwardly at a desk or other work surface reaches rearwardly to grasp a book, telephone, dictation equipment, or other similar articles, the upper portion of the user's body normally moves laterally, and twists or rotates with respect to the user's torso. Such body movement is resisted by fixed or rigid chair backs.
Although some shell-type chair backs can flex laterally to accommodate upper body movement, they do not provide firm, consistent support for the user's back, particularly along the user's spine. Furthermore, the laterally flexing action of the chair back is generally not properly tuned with the user's body shape and movements, thereby reducing overall chair comfort and support.